The study aims to determine the efficacy of alfa interferon in the treatment of hemangiomas that are either destructive of tissue, disabling to the patient, or life-threatening. This includes determinig the side-effects and/or complications, if any, of alfa interferon therapy given over a period of time. We will also determine whether urinary and/or serum levels of basic fibroblast growth factor (bFGF) can be used: 1) as a marker of disease activity; 2) as a marker of treatment efficacy; and 3) as a biochemical marker to distinguish between hemangiomas and other vascular anomalies.